Plasma processing apparatus

ABSTRACT

The present invention provides a plasma processing device capable of inducing a strong radio-frequency electric field within a vacuum container while preventing sputtering of the antenna conductor, an increase in the temperature of the antenna conductor and the formation of particles. A plasma processing device according to the present invention includes a vacuum container, a radio-frequency antenna placed between an inner surface and an outer surface of a wall of the vacuum container, and a dielectric separating member for separating the radio-frequency antenna from an internal space of the vacuum container. As compared to a device using an external antenna, the present device can induce a stronger magnetic field in the vacuum container. The separating member has the effects of preventing the radio-frequency antenna from undergoing sputtering by the plasma produced in the vacuum container, suppressing an increase in the temperature of the radio-frequency antenna, and preventing the formation of particles.

TECHNICAL FIELD

The present invention relates to an inductively coupled plasmaprocessing device that can be used for the surface processing of a basebody or for other purposes.

BACKGROUND ART

Inductively coupled plasma processing devices are widely used for thethin-film formation on or the etching process of the surface of a basebody. In inductively coupled plasma processing devices, a plasmaproduction gas, such as hydrogen gas, is introduced into a vacuumcontainer, after which a radio-frequency electric field is induced todecompose the plasma production gas and thereby produce plasma.Subsequently, another kind of gas, which serves as a film-formingmaterial gas or an etching gas, is introduced into the vacuum container.In the former case, the molecules of the film-forming material gas aredecomposed by the plasma and deposited on a base body. In the lattercase, the molecules of the etching gas are decomposed into ions orradicals for the etching process.

Patent Document 1 discloses a plasma processing device using an externalantenna, in which a radio-frequency antenna for inducing aradio-frequency electric field is disposed above the ceiling of thevacuum container and the portion of the ceiling located directly belowthe radio-frequency antenna is made of a dielectric material serving asa window for allowing the passage of the induced radio-frequencyelectric field. In this external antenna type plasma processing device,when the device size is increased to deal with the recent increase inthe size of the base body to be processed, it is necessary to increasethe thickness of the dielectric window in order to maintain itsmechanical strength, which results in a decrease in the strength of theradio-frequency electric field introduced into the vacuum container.Given this problem, an internal antenna type plasma processing device,in which the radio-frequency antenna is provided inside the vacuumcontainer, has also been conventionally used (see Patent Documents 2 and3).

The invention described in Patent Document 3 uses a radio-frequencyantenna consisting of a one-dimensional conductor that is terminatedwithout completing one turn (which corresponds to an inductively coupledantenna with the number of turns less than one), such as a U-shaped orsemicircular antenna. Such a radio-frequency antenna has an inductancelower than that of an inductively coupled antenna whose number of turnsis equal to or greater than one. The lower inductance reduces theradio-frequency voltage occurring at both ends of the radio-frequencyantenna and thereby suppresses radio-frequency fluctuation of the plasmapotential due to electrostatic coupling to the generated plasma. As aresult, an excessive loss of electrons to the ground potential due tothe fluctuation of the plasma potential is decreased, whereby the plasmapotential is decreased. Therefore, a film formation process with a lowlevel of ion damage to the base body can be performed.

BACKGROUND ART DOCUMENT Patent Document

-   Patent Document 1: JP-A 8-227878 (Paragraph [0010] and FIG. 5)-   Patent Document 2: JP-A 11-317299 (Paragraphs [0044]-[0046] and    FIGS. 1-2)-   Patent Document 3: JP-A 2001-035697 (Paragraphs [0050]-[0051] and    FIG. 11)

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

In the internal antenna type plasma processing device, the ions in theplasma are accelerated toward the radio-frequency antenna by a self-biasDC voltage which occurs between the conductor of the radio-frequencyantenna and the plasma. Therefore, the conductor of the radio-frequencyantenna itself undergoes sputtering, which shortens the life of theconductor. Furthermore, the atoms or ions sputtered from the conductorare mixed in the plasma and adhere to the surface of the base body beingprocessed or the inner wall of the vacuum container, causing impuritiesto be mixed in the thin film being formed or the base body being etched.Another problem of the internal antenna type is that the temperature ofthe radio-frequency antenna conductor increases since theradio-frequency antenna conductor is located within the plasma. A changein the temperature of the radio-frequency antenna changes the impedanceof the radio-frequency antenna, which prevents stable supply of power tothe plasma. To address these problems, in the invention described inPatent Document 2, the radio-frequency antenna is sheathed in a pipemade of a dielectric (insulating) material, such as ceramic or quartz,which is less likely to be sputtered than the material of theradio-frequency antenna conductor, such as copper or aluminum, andcooling water is passed through this dielectric pipe. However, thisconfiguration requires both an electrical connector for inputting aradio-frequency power and a connector for supplying or discharging thecooling water to be provided at the ends of the antenna conductor andthe dielectric pipe. Such a structure will be complex, making itdifficult to attach or detach the antenna or perform maintenance andinspection thereof.

In the internal antenna type, since the radio-frequency antennaprotrudes into the internal space of the vacuum container, the plasma isproduced in the vicinity of the radio-frequency antenna. Therefore, theplasma density particularly increases in the vicinity of theradio-frequency antenna and the density distribution becomes lessuniform. Furthermore, since the radio-frequency antenna is locatedwithin the vacuum container, the material of the thin film used in thefilm formation process or a by-product resulting from the etchingprocess may possibly adhere to the surface of the radio-frequencyantenna (or a dielectric pipe around this antenna). Such a material orby-product may fall onto the surface of the base body and form so-calledparticles.

Furthermore, as compared to the external antenna type, the internalantenna type needs a vacuum container having a larger capacity in orderto ensure a space for the radio-frequency antenna within the vacuumcontainer. Therefore, the gas or plasma easily diffuses, which decreasesthe amount of ions or radicals reaching the base body and lowers thefilm-formation rate or etching rate.

The problem to be solved by the present invention is to provide a plasmaprocessing device capable of inducing a strong radio-frequency electricfield within a vacuum container while preventing sputtering of theantenna conductor, an increase in the temperature of the antennaconductor and the formation of particles.

Means for Solving the Problems

A plasma processing device according to the present invention aimed atsolving the aforementioned problem includes:

a) a vacuum container;

b) an antenna-placing section provided between an inner surface and anouter surface of a wall of the vacuum container;

c) a radio-frequency antenna placed in the antenna-placing section; and

d) a dielectric separating member for separating the antenna-placingsection from an internal space of the vacuum container.

In the plasma processing device according to the present invention, theradio-frequency antenna is placed in the antenna-placing sectionprovided between the inner and outer surfaces of a wall of the vacuumcontainer. Therefore, a stronger radio-frequency electric field can beinduced within the vacuum container as compared to the external antennatype.

Since the radio-frequency antenna is separated from the internal spaceof the vacuum container by a dielectric separating member, the formationof particles and the sputtering of the radio-frequency antenna areprevented. Simultaneously, an increase in the temperature of theradio-frequency antenna is suppressed.

Since it is unnecessary to provide a space for placing theradio-frequency antenna within the vacuum container, the capacity of thevacuum container can be smaller than in the case of the internal antennatype. Therefore, the diffusion of the gas or plasma is suppressed, whichincreases the amount of ions or radicals reaching the base body andimproves the film-formation rate or the etching rate.

The separating member may be a dielectric member provided apart from thewall of the vacuum container. Alternatively, if the wall of the vacuumcontainer is made of a dielectric material, a portion of the wall may beused as the separating member.

Although the radio-frequency antenna may be embedded in the wall, it iseasier to place it in a hollow space formed between the aforementionedinner and outer surfaces. In the former case, the portion of the wall ofthe vacuum container in which the radio-frequency antenna is embeddedcorresponds to the antenna-placing section. In the latter case, thehollow space corresponds to the antenna-placing section.

The hollow space may be a hermetically closed space. This designprevents foreign matters from entering the hollow space. When thishollow space is in the vacuum state or filled with an inert gas, nounnecessary electric discharge occurs in the hollow space.

The hollow space may be filled with a solid dielectric material. Thisalso prevents the occurrence of unnecessary electric discharge in thehollow space. In this case, it is unnecessary to hermetically close thehollow space. Instead of using the hollow space, it is possible to adoptthe structure in which at least a portion of the wall is made of a soliddielectric and the radio-frequency antenna is embedded in the soliddielectric.

A cover may be provided on the outer-surface side of the hollow space.The use of such a cover facilitates maintenance, inspection or similartasks; when the cover is opened, the radio-frequency antenna can beeasily removed from the hollow space through the wall of the vacuumcontainer to the outside and then set to the original position.Furthermore, the radio-frequency antenna may be fixed to the cover. Inthis case, users can more easily remove or set the radio-frequencyantenna by merely detaching or attaching the cover.

The plasma processing device according to the present invention may beprovided with a plurality of antenna-placing sections. This designfurther improves the uniformity in the density of the plasma createdwithin the vacuum container.

Effect of the Invention

The plasma processing device according to the present invention iscapable of inducing a strong radio-frequency electric field within avacuum container while preventing sputtering of the antenna conductor,an increase in the temperature of the antenna conductor and theformation of particles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a vertical sectional view of the first embodiment of theplasma processing device according to the present invention and FIG. 1Bis a vertical sectional view of a radio-frequency antenna unit 20 usedin this plasma processing device.

FIGS. 2A-2C are a perspective view, a top view and a side view showingthe shape of a radio-frequency antenna 21 used in the plasma processingdevice of the present embodiment.

FIG. 3 is a top view showing one example of the connection betweenradio-frequency antennae and radio-frequency power sources.

FIG. 4 is an enlarged vertical sectional view showing a first variationof the first embodiment.

FIG. 5 is an enlarged vertical sectional view showing a second variationof the first embodiment.

FIG. 6 is an enlarged vertical sectional view of the second embodimentof the plasma processing device according to the present invention.

FIG. 7 is an enlarged vertical sectional view of the third embodiment ofthe plasma processing device according to the present invention.

FIG. 8 is an enlarged vertical sectional view of the fourth embodimentof the plasma processing device according to the present invention.

FIG. 9A is an enlarged vertical sectional view of the fifth embodimentof the plasma processing device according to the present invention, andFIG. 9B is a top view of the radio-frequency antenna 41 used in thisembodiment,

FIG. 10 is an enlarged vertical sectional view of the sixth embodimentof the plasma processing device according to the present invention.

FIG. 11A is an enlarged vertical sectional view of the seventhembodiment of the plasma processing device according to the presentinvention, and FIG. 11B is a top view showing the construction of aFaraday electrode 51 and surrounding components.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the plasma processing device according to the presentinvention are hereinafter described by means of FIGS. 1A-11B.

First Embodiment

FIG. 1A is a vertical sectional view of a plasma processing device 10 ofthe first embodiment. This plasma processing device 10 includes a vacuumcontainer 11, a base-body holder 12 placed in the internal space 112 ofthe vacuum container, a gas discharge port 13 and gas introduction ports14 provided in the side wall of the vacuum container 11, hollow spaces(antenna-placing sections) 113 provided between the outer surface 111Aand the inner surface 111B of the top wall 111 of the vacuum container11, a separating member (separating plate) 16 for separating the hollowspace 113 from the internal space 112 of the vacuum container, and aradio-frequency antenna unit 20 attached to the hollow space 113 fromthe side of the outer surface 111A.

The separating member 16 is made of a dielectric material. Examples ofthe available materials include oxides, nitrides, carbides andfluorides. Among these materials, quartz, alumina, zirconia, yttria,silicon nitride or silicon carbide can be suitably used.

A step 111C protruding inwards is formed at the lower end of the innercircumferential surface of the hollow space 113. The separating plate 16is fixed to this step 111C in such a manner that its outercircumferential edge is mounted on the step 111C. The cover 23 has aprojecting portion on its lower surface so that it can fit in the hollowspace 113 from the outside of the vacuum container 11.

The gas discharge port 13 is connected to a vacuum pump. By this vacuumpump, the air, steam and other contents in the internal space 112 of thevacuum container are discharged through the gas discharge port 13 tocreate a high vacuum state. The gas introduction port 14 is used forintroducing a plasma production gas (e.g. hydrogen gas) and afilm-forming material gas into the internal space 112 of the vacuumcontainer. The base body S to be held on the base-body holder 12 isloaded into the internal space 112 of the vacuum container or unloadedfrom the same space through a base-body transfer opening 15 formed inthe side wall of the vacuum container 11. The base-body transfer opening15 is hermetically closed except when the base body is loaded into orunloaded from the vacuum container.

The radio-frequency antenna unit 20 is hereinafter described. FIG. 1B isa vertical sectional view showing the hollow space 113 and surroundingcomponents, including the radio-frequency antenna unit 20. Theradio-frequency antenna unit 20 consists of a cover 23 and aradio-frequency antenna 21, the cover 23 being made of a metal (e.g.stainless steel) closing the hollow space 113 from the outside of thevacuum container 11.

The radio-frequency antenna 21 is placed within the hollow space 113,with both ends fixed to the cover 23 via feedthroughs 24. Since theradio-frequency antenna 21 is fixed to the cover 23 in this manner, theradio-frequency antenna 21 can be easily detached from or attached tothe plasma processing device by detaching or attaching the cover 23. Theradio-frequency antenna 21 consists of an electrically conductive pipe,through which a cooling water or similar coolant can be passed. One endof the radio-frequency antenna 21 is connected to the radio-frequencypower source, while the other end is connected to a ground.

The shape of the radio-frequency antenna 21 is hereinafter described. Asshown in FIGS. 2A-2C, the radio-frequency antenna 21 includes a firstU-shape part 212A and a second U-shape part 212B consisting of twoU-shaped pipes arranged parallel to the separating member 16, with eachpipe having its two ends directed to those of the other pipe. One end212A1 of the first U-shape part 212A is connected to one end 212B1 ofthe second U-shape part 212B by a straight connection part 212C. Theother ends 212A2 and 212B2 of the first and second U-shape parts 212Aand 212E are bent upward and connected to the cover 23.

The cover 23 is provided with a hollow-space exhaust port 25 forevacuating the hollow space 113. The gaps between the radio-frequencyantenna 21 and the feedthrough 24, between the feedthrough 24 and thecover 23, between the cover and the top wall 111, and between theseparating member 16 and the top wall 111 are hermetically sealed byvacuum seals. The hollow space 113 is maintained in a high vacuum stateby the hollow-space exhaust port 25 and the vacuum seals.

One example of the connection between the radio-frequency antennae 13and radio-frequency power sources is hereinafter described by means ofFIG. 3. FIG. 3 is a top view of the plasma processing device 10 of thepresent embodiment. The device of the present embodiment uses a total ofeight radio-frequency antennae 21 contained in eight hollow spaces 113,respectively. These eight radio-frequency antennae 21 are divided intotwo groups, each group including four antennae, and one radio-frequencypower source is connected to each group. A power supply end 211 of eachof the radio-frequency antennae 21 is connected to each of the fourpower supply rods 32 extending from a power supply point 31 in fourdirections. The aforementioned radio-frequency power source is connectedto that point 31.

As one example of the operation of the plasma processing device 10 ofthe present embodiment, the process of depositing a film-formingmaterial on the base body S is hereinafter described. Initially, a basebody S is loaded through the base-body transfer opening 15 into theinternal space 112 of the vacuum container and placed onto the base-bodyholder 12. After the base-body transfer opening 15 is closed, the vacuumpump is energized, whereby the air, steam and other contents in theinternal space 112 of the vacuum container are discharged through thegas discharge port 13, and the air, steam and other contents in thehollow space 113 are also discharged through the hollow-space exhaustport 25. Thus, the internal space 112 of the vacuum container and thehollow space 113 are evacuated. Subsequently, a plasma production gasand a film-forming material gas are introduced from the gas introductionport 14. A radio-frequency power is supplied to each radio-frequencyantenna 21, while a coolant is passed through the pipe of theradio-frequency antenna 21. By this radio-frequency power supply, aradio-frequency electric field is induced around the radio-frequencyantenna 21. This radio-frequency electric field is introduced throughthe dielectric separating member 16 into the internal space 112 of thevacuum container and ionizes the plasma production gas, whereby plasmais produced. The film-forming material gas, which has been introducedinto the internal space 112 of the vacuum container together with theplasma production gas, is decomposed by the resultant plasma, to bedeposited on the base body S.

As compared to the external antenna type, the plasma processing device10 of the present embodiment can create a stronger radio-frequencyelectric field within the internal space 112 of the vacuum container 11since the radio-frequency antenna 21 is located in the hollow space 113provided between the outer surface 111A and the inner surface 111B ofthe top wall 111 of the vacuum container. The separation of the hollowspace 113 including the radio-frequency antenna 21 from the internalspace 112 of the vacuum container by the separating member 16 has theeffects of: preventing plasma produced in the aforementioned space frometching the radio-frequency antenna 21 and shortening its life;preventing the material of the radio-frequency antenna 21 from becomingan impurity to be mixed in the film being formed or the base body beingprocessed; and preventing the formation of particles. Furthermore, sincethe hollow space 113 in which the radio-frequency antenna 21 is placedis maintained in a high vacuum state, no unnecessary electric dischargeoccurs in the hollow space 113.

In the present embodiment, a magnetic field created in the first U-shapepart 212A of the radio-frequency antenna 21 by an electric currentflowing from one end 212A1 to the bottom part of the U-shaped body, anda magnetic field created by an electric current flowing from the bottompart of the U-shaped body to the other end 212A2, have verticalcomponents oscillating in the same phase. Magnetic fields having suchvertical components are similarly created in the second U-shape part212B. As a result, the magnitude of the vertical component of themagnetic field below the antenna will be greater than in the case ofusing a single straight radio-frequency antenna. Therefore, as comparedto the case of using a single straight radio-frequency antenna, a higherplasma density can be achieved under the same strength of theradio-frequency power and/or the same pressure of the plasma productiongas, or the same plasma density can be achieved under a lower strengthof the radio-frequency power and/or a lower pressure of the plasmaproduction gas.

A first variation of the first embodiment is hereinafter described bymeans of FIG. 4. In the present variation, the top wall 111 has no step111C; the separating member 16A is arranged so that it covers the hollowspace 113 on the side facing the internal space 112 of the vacuumcontainer. With this design, the hollow space 113 is expanded toward theinternal space 112 of the vacuum container and the radio-frequencyantenna 21 can be brought closer to the internal space 112 of the vacuumcontainer. The other structural elements are the same as those of thepreviously described embodiment.

A second variation of the first embodiment is hereinafter described bymeans of FIG. 5. In the present variation, a hollow space 113A iscreated by boring a hole from the lower surface of the top wall 111without completely penetrating through the top wall 111. Accordingly, aportion of the top wall 111 remains intact above the hollow space 113A.The radio-frequency antenna 21 is fixed to this remaining portion of thetop wall 111 via feedthroughs. The hollow-space exhaust port 25C is alsoprovided in that portion of the top wall 111. The structure of theseparating member 16A is the same as that of the first variation.

Second Embodiment

A plasma processing device of the second embodiment is hereinafterdescribed by means of FIG. 6. In the present embodiment, a hollow-spaceinert-gas introduction port 25A and a hollow-space gas discharge port25B are provided in the cover 23 of the radio-frequency antenna unit 20Ain place of the hollow-space exhaust port 25 in the first embodiment.The hollow space 113 can be filled with an inert gas, such as argon ornitrogen, by introducing the inert gas through the hollow-spaceinert-gas introduction port 25A to replace air and steam in the hollowspace 113 by the inert gas and discharge the air and steam through thehollow-space gas discharge port 25B to the outside. As a result, similarto the case of evacuating the hollow space 113, the occurrence ofunnecessary electric discharge is prevented. The other structuralelements are the same as those of the first embodiment.

Third Embodiment

A plasma processing device of the third embodiment is hereinafterdescribed by means of FIG. 7. In the present embodiment, the hollowspace 113 is filled with a dielectric member 27. Examples of thematerials for the dielectric member 27 include polytetrafluoroethylene(PTFE), polyether ether ketone (PEEK) and other resins as well asalumina, silica and other ceramics. The bottom portion of the dielectricmember 27 functions as the separating member. The radio-frequencyantenna 21, which is U-shaped similar to the previous embodiment, isdirectly fixed to the cover 23 without using feedthroughs. Since theradio-frequency antenna 21 is fixed to the cover 23 in this manner, boththe radio-frequency antenna 21 and the dielectric member 27 around thisantenna 21 are attached to or detached from the vacuum container 11 whenthe cover 23 is attached to or detached from this container 11.Accordingly, it can be said that the radio-frequency antenna 21, thecover 23 and the dielectric member 27 in the present embodiment form oneset of the radio-frequency antenna unit 20B.

In the third embodiment, since the hollow space 113 is filled with thedielectric member 27, no unnecessary electric discharge occurs in thevicinity of the radio-frequency antenna 21.

In place of the dielectric member 27, a dielectric powder may be filledinto the hollow space 113. In this case, the hollow space 113 should behermetically closed so that the powder will not leak from the hollowspace 113.

Fourth Embodiment

In any of the previous examples, the radio-frequency antenna 21 wasprovided within the hollow space 113. However, it is possible to embedthe radio-frequency antenna 21 between the outer surface 111A and theinner surface 111B without using any hollow space, as shown in FIG. 8,where the region denoted by numeral 113B corresponds to theantenna-placing section. In this case, in order to electrically insulatethe radio-frequency antenna 21 from the top wall 111 and to preventunnecessary electric discharge from occurring in the vicinity of theradio-frequency antenna 21, a dielectric member should be providedbetween the radio-frequency antenna 21 and the top wall 111, or the topwall 111 should be made of a dielectric material. In the latter case,the top wall 111 may be entirely made of the dielectric material.However, for the sake of the cost reduction, it is preferable to use thedielectric material only in the portion of the top wall 111 near theradio-frequency antenna 21. For the herein mentioned dielectricmaterial, the previously listed materials of the dielectric member 27are similarly available. The portion of the top wall 111 located betweenthe radio-frequency antenna 21 and the internal space 112 of the vacuumcontainer may be made of a dielectric material so that this portionfunctions as a separating plate 16B.

Fifth Embodiment

One example using a radio-frequency antenna having a shape differentfrom any of the previous embodiments is described by means of FIGS. 9Aand 9B. As shown in FIG. 9B, the radio-frequency antenna 41 in thepresent embodiment consists of one electrically conductive pipe spirallywound in a plane parallel to the separating member 16. The otherstructural elements are the same as those of the first embodiment. Byusing the radio-frequency antenna 41 having such a shape, it is possibleto create a magnetic field over a larger area than in the case of usinga straight or U-shaped radio-frequency antenna.

Sixth Embodiment

In any of the previous embodiments, there was only one radio-frequencyantenna placed in each antenna-placing section (hollow space). However,it is possible to provide two or more radio-frequency antennae in oneantenna-placing section. In the example shown by the top view in FIG.10, two radio-frequency antennae 21 described in the first embodiment(first radio-frequency antenna 21A and second radio-frequency antenna21B) are provided in the hollow space 113. The first and secondradio-frequency antennae 21A and 21B are arranged so that their firstand second U-shaped parts 212A and 212B are at the same distance fromthe separating member 16 and their connection parts 212C are parallel toeach other.

Seventh Embodiment

A seventh embodiment of the plasma processing device according to thepresent invention is described by means of FIGS. 11A and 11B. The plasmaprocessing device of the present embodiment is a variation of the plasmaprocessing device 10 of the first embodiment and further includes aFaraday shield 51 placed on the separating member 16 (between theseparating member 16 and the radio-frequency antenna 21). The Faradayshield 51 is electrically connected to the metallic top wall 111 andfurther to a ground via the top wall 111. The Faraday shield 51 stops aDC electric field produced by a self bias between the conductor of theradio-frequency antenna 21 and the plasma and thereby prevents plasmaproduced in the internal space 112 from impinging on the separatingmember 16, so that the life of the separating member 16 will beincreased. A dielectric insulating member 52 is inserted between theFaraday shield 51 and the radio-frequency antenna 21 in order to preventelectric discharge from occurring in the space between the shield andthe antenna.

In the Faraday shield 51, an almost entire portion of the lower surfaceis thermally in contact with the separating member 16, with both endsthermally connected to the top wall 111. Therefore, the heat from theseparating member 16, which receives energy from the plasma and becomeshotter, is released through the Faraday shield 51 to the top wall 111.In this manner, an increase in the temperature of the separating member16 is suppressed and the degradation of the separating member 16 due tothe heat is prevented. To further improve this effect, the Faradayshield 51 may be cooled by a coolant, or a means for suppressing thetemperature increase, such as a cooling pipe, may be additionallyprovided apart from the Faraday shield 51.

Other Embodiments

The number of radio-frequency antennae 21, which was eight in theprevious embodiments, can be appropriately determined according to thecapacity of the vacuum container or other factors. Using only oneradio-frequency antenna 21 may be sufficient for a vacuum containerhaving a rather small capacity. Unlike the previous embodiments, inwhich the radio-frequency antenna unit 20 was provided in the top wallof the vacuum container, the radio-frequency antenna unit may beprovided in a different wall, such as the side wall.

EXPLANATION OF NUMERALS

-   10 . . . . Plasma Processing Device-   11 . . . . Vacuum Container-   111 . . . . Top Wall of Vacuum Container-   111A . . . . Outer Surface of Top Wall of Vacuum Container-   111B . . . . Inner Surface of Top Wall of Vacuum Container-   111C . . . . Step Formed on Top Wall of Vacuum Container-   112 . . . . Internal Space-   113, 113A . . . . Hollow Space (Antenna-Placing Section)-   113B . . . . Antenna-Placing Section-   12 . . . . Base-Body Holder-   13 . . . . Gas Discharge Port-   14 . . . . Gas Introduction Port-   15 . . . . Base-Body Transfer Opening-   16, 16A, 1613 . . . . Separating Member (Separating Plate)-   20, 20A, 20B . . . . Radio-Frequency Antenna Unit-   21, 41 . . . . Radio-Frequency Antenna-   211 . . . . Power Supply End-   21A . . . . First Radio-Frequency Antenna-   21B . . . . Second Radio-Frequency Antenna-   212A . . . . First U-Shaped Part-   212B . . . . Second U-Shaped Part-   212C . . . . Connection Part-   23 . . . . Cover-   24 . . . . Feedthrough-   25, 25C . . . . Hollow-Space Exhaust Port-   25A . . . . Hollow-Space Inert-Gas Introduction Port-   25B . . . . Hollow-Space Gas Discharge Port-   27 . . . . Dielectric Member-   31 . . . . Power Supply Point-   32 . . . . Power Supply Rod-   51 . . . . Faraday Shield-   52 . . . . Insulating Member-   S . . . . Base Body

1-2. (canceled)
 3. The plasma processing device, comprising: a) a vacuumcontainer; b) an antenna-placing section provided between an innersurface and an outer surface of a wall of the vacuum container; c) aradio-frequency antenna placed in the antenna-placing section; and d) adielectric separating member for separating the antenna-placing sectionfrom an internal space of the vacuum container.
 4. The plasma processingdevice according to claim 3, wherein the antenna-placing section is ahollow space formed between the aforementioned inner surface and theouter surface.
 5. The plasma processing device according to claim 4,wherein the hollow space is a hermetically closed space.
 6. The plasmaprocessing device according to claim 5, wherein the hollow space is avacuum.
 7. The plasma processing device according to claim 5, whereinthe hollow space is filled with an inert gas.
 8. The plasma processingdevice according to claim 4, wherein the hollow space is filled with asolid dielectric material.
 9. The plasma processing device according toclaim 3, wherein at least a portion of the wall is made of a soliddielectric and the radio-frequency antenna is embedded in the soliddielectric.
 10. The plasma processing device according to claim 3,wherein a plurality of the radio-frequency antennae are provided in oneantenna-placing section.
 11. The plasma processing device according toclaim 3, wherein a grounded electrode is provided between theradio-frequency antenna and the separating member.
 12. The plasmaprocessing device according to claim 11, wherein a dielectric insulatingmember is inserted between the radio-frequency antenna and the groundedelectrode.
 13. The plasma processing device according to claim 11,wherein the grounded electrode is a Faraday shield.
 14. The plasmaprocessing device according to claim 11, wherein the grounded electrodeis made to be in contact with the separating member so as to suppress anincrease in a temperature of the separating member.
 15. The plasmaprocessing device according to claim 3, further comprising a mechanismfor suppressing an increase in a temperature of the separating member.16. The plasma processing device according to claim 3, wherein theseparating member is made of a material selected from a group of oxides,nitrides, carbides and fluorides.
 17. The plasma processing deviceaccording to claim 16, wherein the separating member is made of amaterial selected from a group of quartz, alumina, zirconia, yttria andsilicon nitride and silicon carbide.
 18. The plasma processing deviceaccording to claim 3, comprising a plurality of the antenna-placingsections.
 19. The plasma processing device according to claim 4, furthercomprising a cover provided on a side of the antenna-placing sectionfacing the aforementioned outer surface.
 20. The plasma processingdevice according to claim 19, wherein the radio-frequency antenna isattached to the cover.